Evaluating and Improving the Usability of Mechanical Turk ...billthies.net/dev10-slides.pdf · Evaluating and Improving the Usability of Mechanical Turk for Low-Income Workers in

Evaluating and Improving the Usability of Mechanical Turk for Low-Income Workers in IndiaShashank Khanna, IIT BombayAishwarya Ratan, Microsoft Research IndiaJames Davis, UC Santa CruzBill Thies, Microsoft Research India

The Rise of Paid Crowdsourcing

• In the last decade, over 1 million workers have earned $1-2 billion via crowdsourced work

• Opportunity for workers in developing regions?

– Eliminates need for co-location and formal contracts

– Flexible hours – can work in “free time”

*

* B. Frei. Paid Crowdsourcing: Current State & Progress towards Mainstream Business Use. Smartsheet White Paper, Sep 2009 2

Mechanical Turk Changes Lives in India

• 36% of MTurk workers are in India *Ross’10+

• From our survey of 200 Indian Turkers (July 2010):

“I’m from a middle class family. After completing my degree I looked for job everywhere but failed. But whenI found MTurk, it changed my life. It helped me a lot.”— 26-year old college graduate from Kolkata. Earns $1860 / year on Turk.

— Respondent from Trichy. Earns $1600 / year on Turk.

“MTurk [is] really an advantage to me, it helps me to pay my college fees myself. It made me to feel I’m on my own. I got the respect while studying by this reasonable income.”

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But Most Users are in High-Income Group

0% 20% 40% 60% 80% 100%

Have PC + Internetat home

Have Bachelor'sdegree

Indian Turkers

Indian Average

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15% of incomefrom MTurk

$0 $2,000 $4,000

Annual individual income

But Most Users are in High-Income Group

0% 20% 40% 60% 80% 100%

Have PC + Internetat home

Have Bachelor'sdegree

Indian Turkers

Indian Average

15% of incomefrom MTurk

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$0 $2,000 $4,000

Annual individual income

Our Study: Evaluating and Improving MTurk for Low-Income Workers in India

• Methods:

– Observe 7 users attempting various tasks on MTurk

– Pick a single task (bounding box), iteratively refine UI

– Evaluate 5 variations of user interface across 49 users

• Results:

– The UI is a bottleneck for low-income users on MTurk

– Language localization is necessary, but not sufficient

– Simplified interfaces and task instructions can boost completion of bounding box task from 0% to 66%

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Closely Related Work

• Samasource

• txteagle

• CrowdFlower

• Prior studies of MTurk *Ross’10+ *Ipeirotis’10+

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In This Talk

• Usability Barriers

• Iterative Design

• Earning Potential

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Focus: Lower-Income Urban Users

• Participants from two locations:– Office support staff: security guards,

housekeeping, maintenance staff, etc.

– Nonprofit IT training center: memberswith and without jobs, many students

• Median education: 12 years

• Median income: $1330 / year– 2nd quintile (20-40%) for urban India

• Went to local-language school,but know basic English

• Have basic digital literacy,but no exposure to MTurk

Outside the IT training center

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Initial Observations

• With each of 7 participants:

• Participant registers on MTurk and attempts 1-2 tasks

• Hour-long 1-on-1 session, providing help if needed

VerifyAddress

Test New CAPTCHA

LabelImage

Input Method Text Graphical Graphical

Output Method Text Text Graphical

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VerifyAddress

Test New CAPTCHA

LabelImage



Inherent Barriers toCompleting Task

• Evaluatingtrust on Web• Nuanced use of language

• Ignoring truly illegible letters• Converting to unformatted text

(Unfamiliarwith using click-and-drag interaction)

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VerifyAddress

Test New CAPTCHA

LabelImage







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VerifyAddress

Test New CAPTCHA

LabelImage







13





VerifyAddress

Test New CAPTCHA

LabelImage







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Usability Barriers Across Tasks

Minimal separation of general and task-specific navigation

Need to click “Accept Hit” prior to starting work

Going back in browser will lose work; need to click here to go back

Hard to find help

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Difficulty Understanding the Instructions

Use of advanced language (“occluded”)

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Difficulty Understanding the Instructions

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System is Unusable Without Assistance

• None of 9 users could label an image in 30 min

• Methodology used in this talk:

– Task: outline an object (lamp) in each of 20 images

▪ Or indicate that no lamp is present

▪ Maximum time: 30 minutes

– Users receive an overview of MTurk

– But NO assistance is offered inunderstanding or doing the task

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Iterative Design and Evaluation

Design 1: Translation to Local Language

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Still, none of 10 participants could

successfully outline and submit an image

Design 2: New Instructions and Interface

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Original Instructions New Instructions

Add StructureSimplify Language

Improve Illustrations

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Add StructureSimplify Language

Improve Illustrations


Original Instructions New Instructions

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Search and find the fish in the picture, and then draw a box around it. To draw the box, usethe computer’s mouse.

• In this project we will show you some pictures.• You will get a target object.• In each picture, you should search for that

object and draw a box around it.

For example: In this picture, your target is fish.

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25


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• In this picture, your target is: lamp.• Look for the lamp in each picture and draw a box over it.

The target is not present in this picture.

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Evaluation

Design Images Annotated Correctly

0. Original MTurk (English) 0

1. Original MTurk (Kannada) 0

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Evaluation




2. New Instructions, New Interface (Kannada) 66%

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Evaluation





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Evaluation





3. Video Instructions, New Interface (Kannada)

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Evaluation





3. Video Instructions, New Interface (Kannada) 63%

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Evaluation






33

Evaluation






4. Video Instructions (Kannada),Original Interface (English)

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Evaluation







40%

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Evaluation







40%

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Sources of Error

Correct66%

Skipped4%

Box too large11%

Mark lamp where none

exists,or fail to

mark lamp in image19%

Mark

Marked object where none exists,or failed to mark object in image

19%

(Fix with UI change)

(Fix with pre-test)

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Errors Due to Cultural Context?

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Errors Due to Cultural Context?

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Errors Due to Intrinsic Difficulty of Task

Disagreementamong authors:

Participant found lamp that we did not:

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Workers’ Earning Potential

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Workers’ Earnings Potential

• Bounding box tasks pays $0.05 for 20 images

– Accuracy requirements unknown (we assume 75%)

Time toSubmit 20 Images

GrossPayment

Median participant 7m 20s $0.41 / hr

• Baseline wage for median participant is $0.83 / hr

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GrossPayment

Fastest participant 1m 32s $1.96 /hr

Median participant 7m 20s $0.41 / hr

Slowest participant 23m 49s $0.13 / hr


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GrossPayment

Net Earnings (paying $0.30 / hr for Internet)

Fastest participant 1m 32s $1.96 /hr $1.52 / hr

Median participant 7m 20s $0.41 / hr $0.11 / hr

Slowest participant 23m 49s $0.13 / hr -$0.17 / hr


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Conclusions

• MTurk has yet to reach low-income workers in India

• We expose new barriers to usage by this group– Textual tasks difficult, but graphical tasks within reach– Current instructions and interfaces are a bottleneck

• We demonstrate that new designs can overcome barriers, improving image labeling from 0 to 66%

• Additional research needed to improve earnings– Increasing speed of task completion– Reducing cost of computer access– Making it easier to author usable tasks

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Extra Slides

Design RecommendationsHow to Design Microtasking Sites for Low-Income Workers?

• Improved instructions and interfaces are needed

– Use simple, clear illustrations for each task

– Minimize visual complexity

– Streamline navigation

– Anticipate sequencing of steps

• Language localization is necessary but not sufficient

• Video instructions work comparably to simplified text instructions, and thus are unlikely to be worth it

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MTurk and Professional Development

• Microtasking can pose hazards to workers *Zittrain’08+

– No affiliation with a team

– Inability to understand moral implications of work

– No working regulations, e.g., on wages or hours

• Is not necessarily limited to menial tasks– Creative tasks: design logos, taglines, graphics, etc.

– Skilled tasks: writing, copyediting, programming, etc.

– Thus could be a pathway to higher-level employment

• Might be more suitable for supplemental income– Offers extreme flexibility relative to other employment

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Documents

Evaluating and Improving the Usability of Mechanical Turk ...billthies.net/dev10-slides.pdf · Evaluating and Improving the Usability of Mechanical Turk for Low-Income Workers in